1. Field of the Invention
The present invention relates to a mechanism in the field of rotary compressors and pumps.
2. State of the Art
Nowadays, there are some mechanisms having similar systems to the one proposed that have not yet been commercialized.
These compressors having a design with tangential cylinders comprise a casing with a crank in the center and two or more two-armed structured levers with a turn axis inside, which engages a shaft that is radially located at the casing.
At the outer arm of this lever, the piston is connected via a connecting rod whereas at the inner arm a slot has been made in which the crank stem slides, with the whole assembly rotating with all elements coupled thereto about the crank shaft, which remains static after being anchored to the structure.
This arrangement causes the lever, which is driven by its shaft, to pivot about the latter forced by the eccentric stem of the crank when rotating the assembly, thereby producing an oscillation per rotation of the assembly, which linearly moves the piston that is attached to the outer arm.
In this structure in which a force is applied on the fulcrum (turn axis), the inner arm acts as the power arm and behaves as a lever of third order that is inefficient. In addition, when the crank stem moves along the slot, the power arm distance increases or decreases largely, thus making fast-changing torques causing the assembly instability.
As is well known, the lever is a device used for many centuries and in particular, the one proposed in this mechanical system, with one of its so saying “floating” points, is being used extensively in the textile and food industry and in many types of machines, from which it is obvious that no one attempts to patent a lever having said characteristics, but a mechanical system enabling the production of a rotary assembly to transform a circular movement into a linear movement through the interaction of this with a crankshaft.
For a couple of decades, a mechanism having the aforementioned characteristics has been tried to be developed by the same author, initially based on the idea of using an assembly that rotates about a crank and having a slotted lever that pivots about an axis located in the central area thereof. The force is applied on this axis and the journal of the crank slides along the slotted area located in the inner arm, which acts as a fulcrum. In this way, as the assembly rotates and the journal of the crank slides along the grooved area, since it remains static anchored to the structure supporting the assembly, it produces a tilting movement on the lever that is transmitted to the resistance arm and from this to a piston by means of a connecting rod and a piston, thus causing the linear movement thereof along a cylinder tangentially located. This lever is classified as of third order (the force is applied at the center) and, as it is known, it does not produce any advantage, but the project was continued with the understanding that the benefits obtained by the rotation would be important.
Several prototypes have been developed in principle with a crank (crankshaft with only one journal) and subsequently with a crankshaft with two and three journals for machines of two or three cylinders in an attempt to statically balance the assembly. After several prototypes, the project was abandoned because the design of the proposed mechanism did not produce any benefit and the vibrations it originated (apparently because the sliding of the fulcrum along the inner groove continuously changes the length of the power arm) prevented the rotation at relatively low speeds. This information relates exclusively to rotary piston compressors; European Patent EP1749685 and Spanish Patents ES2065801 and ES2263331, and the inventor is not aware of others having these features.
After several attempts to solve these problems, an innovation has been found that not only overcomes this impediment, but also provides stability to the mechanism, which makes it highly efficient. This new mechanism is based on an assembly, consisting of a unit comprising two housings, wherein a lever anchored by a shaft, about which it pivots and which is arranged at one of its ends, is located, which has a slotted central area and also rotates about a crankshaft. By rotating the unit, the force applied on the shaft about which the lever pivots and as it slides along the grooved area on the crank journal, which acts as a fulcrum and which is stationary and anchored to the structure or support of the assembly, produces an oscillation of the lever that results in a linear movement of the other end and which, by means of a connecting rod, is applied to a piston sliding into a cylinder radially located in the assembly.
As clearly seen, the fundamental difference between the two systems is that in the first the crankshaft actuates on the power arm by changing its length and causing the tilting movement of the lever whereas the resistance arm does not change, thereby and depending on the position in the rotation during a sector, it is greater than the power arm so, according to this design, the lever does not produce any benefit by acting as a third-order lever and causes vibrations which make the project unfeasible. In the system that is currently proposed, the crank acts as a fulcrum and at the same time it causes the oscillation of the lever during the rotation and changes the relationship between the power-resistance arms, increasing the first one during the working stroke and decreasing it in the suction stroke (this new feature allows to greatly improve the lever arm and the piston stroke with small variations in the diameter of the crankshaft) and the lever acts as a first-order one in the first case and as a second-order one in the following case, thus significantly improving the efficiency of the mechanism while the vibrations are eliminated.
This mechanism, with the same design, can be used as a vacuum pump. For this purpose, the rotation is inverted in order to take advantage of the maximum length of the lever arm during the operating step. Also the suction and discharge inlet and outlet are invested in such a way that the aspiration is performed by the duct of the front shaft and the rotary valve and the gas is directly expelled outside through the discharge valve of the cylinder head.
As previously mentioned, this device works by acting on a first-order lever, wherein the crankshaft is the fulcrum, and the eccentricity of the journals results in linear movement of the piston, since the entire assembly (casing, cylinders, rods, pistons, cylinder heads, recovery pumps and levers) rotates about said crankshaft, i.e., it must remain static so that the entire assembly works for the purpose it is intended to be used. This feature means that if we act by releasing and locking the crankshaft at will, it allows the mechanism to rotate freely on a bed without creating more strength than that of the rotation when it is released, or to produce compression or vacuum energy as required when it is locked. Thus, we can reduce the workload during the start and if we couple the drive mechanism to the drive axle of a vehicle and provide it with a clutch or brake, which can act to lock the crankshaft when required, it can be used to assist braking and recover energy during the same.